Adderall -- a brand of amphetamine salts -- is a central nervous stimulant, or CNS. It is used in the treatment of attention deficit hyperactivity disorder, also known as ADHD. Caffeine is a naturally occurring substance found in a variety of plants, such as coca pod, cola nut and guarana. It is also in sodas, coffee, tea, chocolate and energy drinks. It, too, is considered a central nervous system stimulant, although a mild one. Adding two stimulant drugs together results in a more pronounced stimulation of your CNS. Therefore, taking caffeine with Adderall primarily makes potential side effects more severe.
Individually, caffeine and Adderall adversely affect the heart. They both increase your heart rate. According the prescribing information for Adderall, your heart rate is potentially increased by about three to six beats per minute when you take it. When caffeine and Adderall are taken together, your heart rate increases more.
Blood Pressure Effects
Caffeine and Adderall also raise your blood pressure. A normal blood pressure is less than 140/90 mm/Hg. Adderall alone may raise your average blood pressure approximately 2 to 4 mm/Hg. Add it to caffeine and you are likely to see and even greater increase in your blood pressure.
Insomnia and Nervousness
Both caffeine and Adderall can cause you to have trouble falling asleep. In fact, insomnia is one of the more common side effects of Adderall and is one of the reasons that people sometimes drink caffeine-containing products. Adderall and caffeine together may also result in extreme feelings of nervousness, restlessness or jitteriness.
Headache and Tremor
People taking Adderall and caffeine together may experience headaches and tremors. Caffeine's effects depend on the amount of caffeine you consume. If you are addicted to caffeine, you may also develop a headache in response to withdrawal from it.